Method and apparatus for monitoring SAS CPAS performance in CBRS systems

ABSTRACT

A method for monitoring performance of Cooperative Periodic Activity between Spectrum Access Systems (CPAS) process in a network operating Citizens Broadband Radio Service (CRBS). The method comprises performing a first check of a status of a transmission Grant of a Citizens Broadband Radio service Device (CBSD) at the start of the CPAS process and if the result of the first check indicates that the Grant is suspended then performing a second check of the status of said transmission Grant at the end of the CPAS process. The method further comprises raising an alarm if the result of the second check indicates that the Grant is suspended. An apparatus and a network implementing the method are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. application Ser. No.16/712,142, filed Dec. 12, 2019, which claims the benefit of U.S.Provisional Application No. 62/793,448, filed Jan. 17, 2019. Both ofthese earlier applications are hereby incorporated herein by referencein their entireties.

TECHNICAL FIELD

The present invention relates to communications networks, in general,and in particular to operating a communications network using part ofthe spectrum allocated to Citizens Broadband Radio Service.

BACKGROUND

In the USA, the 3.6 GHz (3550 MHz to 3700 MHz) band is already in use byprior incumbents (e.g. US Federal Government for Naval radar systems andDepartment of Defence or existing license holders) but may be used byothers (e.g. telecom operators) where and when not needed by the USgovernment. The Citizens Broadband Radio Service (CBRS) is an initiativethat aims to allow this part of the spectrum to be shared. Telecomoperators might be able to deploy 4G and 5G wireless networks using theCBRS.

This is done using a component called a Spectrum Access System (SAS)which allocates frequencies and transmission power to individualCitizens Broadband Radioservice Devices (CBSDs) based on measurementsand interference modelling calculations. The CBSDs request permission totransmit, and grants are assigned to each CBSD giving frequency andtransmission power. These grants are polled to check whether they (CBSDdevices) are authorized to transmit and the polling (calledheartbeating) gives an authorization to transmit for a few minutes witheach heartbeat. This mechanism is described in more detail in reference[1].

The SAS is the key component that allows the spectrum of the 3.6 GHzband to be shared, but Spectrum Access Systems are provided by multiplevendors and the vendors must synchronize their SASs to allowinterference modelling to occur between vendors' equipment. This is doneusing so called Cooperative Periodic Activity between SASs (CPAS)described in reference [2]. Before CPAS process is complete the CBSDwill get a grant but the grant will not be authorized until the CPASprocess has confirmed the grant with the neighbouring Spectrum AccessSystems.

The CPAS process is opaque and is not easy to monitor and a failure ofthe CPAS process will prevent the CBSDs from transmitting.

SUMMARY

According to a first aspect of the present disclosure there is provideda method of monitoring performance of Cooperative Periodic Activitybetween Spectrum Access Systems, CPAS, process in a network operatingCitizens Broadband Radio Service, CBRS. The method comprises performinga first check of a status of a transmission Grant of a CitizensBroadband Radio service Device, CBSD at the start of the CPAS process.Then, if the result of the first check indicates that the Grant issuspended the method comprises performing a second check of the statusof said transmission Grant at the end of the CPAS process. Further themethod comprises raising an alarm if the result of the second checkindicates that the Grant is suspended.

Preferably the method comprises starting a timer at the start of theCPAS process, wherein the timer expires at the expected completion ofthe CPAS process.

The method may be performed based on information on a single Grant fromone CBSD. Alternatively, a plurality of instances of the method may beperformed for a plurality of CBSDs.

In an alternative embodiment the method may be performed based oninformation on plurality of Grants from a plurality of CBSDs, theplurality of CBSDs being associated with the same SAS, wherein the alarmis raised if Grants are suspended at the beginning and at the end of theCPAS process for more than one of the CBSDs.

The method may be performed at a Domain Proxy, wherein a Domain Proxy, aCBSD or a SAS. A Domain Proxy, DP, represents one or more CBSDs to theSAS.

According to a second aspect of the present disclosure there is providedan apparatus for monitoring performance of Cooperative Periodic Activitybetween Spectrum Access Systems, CPAS, process in a network operatingCitizens Broadband Radio Service, CBRS. The apparatus comprises aprocessing circuitry and a memory. The memory contains instructionsexecutable by the processing circuitry such that the apparatus isoperative to perform a first check of a status of a transmission Grantof a Citizens Broadband Radio service Device, CBSD at the start of theCPAS process. The apparatus is also operative to perform a second checkof the status of said transmission Grant at the end of the CPAS processif the result of the first check indicates that the Grant is suspended.Further, the apparatus is operative to raise an alarm if the result ofthe second check indicates that the Grant is suspended.

Preferably, the apparatus is operative to start a timer at the start ofthe CPAS process, wherein the timer expires at the expected completionof the CPAS process.

Preferably, the apparatus is operative to use information on a singleGrant from one CBSD for monitoring performance of the CPAS process.

Alternatively, the apparatus is operative to use information onplurality of Grants from a plurality of CBSDs, wherein the plurality ofCBSDs being associated with the same SAS, and to raise the alarm ifGrants are suspended at the beginning and at the end of the CPAS processfor more than one of the CBSDs.

The apparatus may comprise a Domain Proxy, a CBSD or a SAS, wherein aDomain Proxy, DP, is operative to represent one or more CBSDs to theSAS.

According to a third aspect of the present disclosure there is providedan apparatus for monitoring performance of Cooperative Periodic Activitybetween Spectrum Access Systems, CPAS, process in a network operatingCitizens Broadband Radio Service, CBRS. The apparatus is adapted toperform a first check of a status of a transmission Grant of a CitizensBroadband Radio service Device, CBSD at the start of the CPAS processand perform a second check of the status of said transmission Grant atthe end of the CPAS process if the result of the first check indicatesthat the Grant is suspended. Further, the apparatus is adapted to raisean alarm if the result of the second check indicates that the Grant issuspended.

According to a fourth aspect of the present disclosure there is provideda communications network comprising an apparatus for monitoringperformance of Cooperative Periodic Activity between Spectrum AccessSystems, CPAS, process in a network operating Citizens Broadband RadioService, CBRS. The apparatus comprises a processing circuitry and amemory. The memory contains instructions executable by the processingcircuitry such that the apparatus is operative to perform a first checkof a status of a transmission Grant of a Citizens Broadband Radioservice Device, CBSD at the start of the CPAS process and to perform asecond check of the status of said transmission Grant at the end of theCPAS process if the result of the first check indicates that the Grantis suspended. Further, the apparatus is operative to raise an alarm ifthe result of the second check indicates that the Grant is suspended.

The communications network according to any one of claims 16-19comprising a Domain Proxy, wherein a Domain Proxy, DP, is operative torepresent one or more CBSDs to the SAS.

BRIEF DESCRIPTION OF THE DRAWINGS

The solution disclosed in this document will be understood andappreciated more fully from the following detailed description taken inconjunction with the drawings in which:

FIG. 1 is a diagram illustrating an interface for communication betweena SAS and CBSD devices or Domain Proxies;

FIG. 2 is a diagram illustrating transitions between unregistered andregistered states of a CBSD;

FIG. 3 is a diagram illustrating transitions between states of a requestto transmit in CBRS band;

FIG. 4 is a diagram illustrating exchange of Heartbeat Requests andHeartbeat Responses between CBSD and SAS;

FIG. 5 is a diagram illustrating one embodiment of a method ofmonitoring performance of CPAS process in CBRS;

FIG. 6 is a diagram illustrating one embodiment of a network operatingin accordance with embodiments of the method illustrated in FIG. 5;

FIG. 7 is a diagram illustrating one embodiment of an apparatus formonitoring performance of CPAS process in CBRS;

FIG. 8 is a diagram illustrating one embodiment of a network operatingin accordance with embodiments of the method illustrated in FIG. 5;

FIG. 9 illustrates timing of the operations of the present solution inin one embodiment.

DETAILED DESCRIPTION

In the following description, for purposes of explanation and notlimitation, specific details are set forth such as particulararchitectures, interfaces, techniques, etc. in order to provide athorough understanding of the disclosed solution. However, it will beapparent to those skilled in the art that the disclosed solution may bepracticed in other embodiments that depart from these specific details.In other instances, detailed descriptions of well-known devices,circuits, and methods are omitted so as not to obscure the descriptionof the disclosed solution with unnecessary details.

Reference throughout the specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with an embodiment is included inat least one embodiment of the present solution. Thus, the appearance ofthe phrases “in one embodiment” or “in an embodiment” in various placesthroughout the specification are not necessarily all referring to thesame embodiment. Further, the particular features, structures orcharacteristics may be combined in any suitable manner in one or moreembodiments.

FIG. 1 illustrates an interface for communication between a SpectrumAccess System, 102, and CBSD devices, 104, or Domain Proxies (DP), 106,which represent one or more CBSD devices, 104, to the SAS, 102, asdescribed in [1]. A Spectrum Access System, 102, is a system thatauthorises and manages the use of the CBRS spectrum by CBSD devices,104. A CBSD device, 104, is a radio device which transmits and receiveswireless communication in the CBRS band. It may be, for example, a radiobase station (e.g. eNodeB) of a wireless network operator capable ofoperating in the spectrum assigned to this network operator as well asin the CBRS band when authorised by the SAS, 102.

A CBSD device in order to operate in the CBRS band must first registerwith a SAS. To register, the CBSD device sends a Registration RequestMessage to the SAS. The information sent in the Registration RequestMessage includes CBSD's power capabilities, location, and antennacharacteristics. The SAS may approve the request and the CBSDtransitions from the initial unregistered state to the registered state.If the SAS rejects the request the CBSD remains in the unregisteredstate. A registered CBSD will transition back to the unregistered stateif it changes its location or antenna characteristics, if it sends aDeregister Request Message or if the SAS orders deregistration for otherreasons. These states and transitions are illustrated in FIG. 2.

The CBSD is not allowed to operate in the CBRS band just yet (i.e.transitioning to the registered state is not enough). States andtransitions leading to the CBSD being allowed to transmit and receive inthe CBRS band are illustrated in FIG. 3. A registered CBSD must firstsend a Grant Request Message to the SAS with which it is registered. ACBSD with no Grant approved is in an Idle state and a CBSD with at leastone Grant approved is in a Granted state. A CBSD may request more thanone Grant from its SAS. A CBSD with a Grant that is ready to commenceoperation in the CBRS band (i.e. in the Granted state) sends a HeartbeatRequest associated with the Grant. If the SAS responds with a HeartbeatResponse (Grant suspended), 302, the CBSD cannot start operation in theCBRS band but continues sending Heartbeat Request associated with theGrant until a Heartbeat Response (success), 304, or Heartbeat Response(Grant terminated), 306-1, is received. Heartbeat Response (success),304, transitions the state to Authorized and the CBSD, while authorised,is allowed to start transmitting and receiving in the CBRS band for theduration of the grant. If a subsequent Heartbeat Request message(s) is(are) responded with Heartbeat Response (success), 304, the CBSDcontinues its operation. If the CBSD in the Authorised state receivesHeartbeat Response (Grant terminated), 306-2, message it transitions tothe Idle state. While in the Idle state the CBSD may send the GrantRequest Message to the SAS with which it is registered and if therequest fails, 308, the CBSD remains in the Idle state. If the requestis successful, 310, the CBSD transitions to the Granted state.

As illustrated in FIG. 4 there may be multiple Heartbeat Requests sentuntil a success Heartbeat Response is received and then Heartbeatrequests are continued to be transmitted by the CBSD. As long as a“success” response is received the CBSD is allowed to operate. Theauthorization allows to transmit for a defined period (e.g. few minutes)with each heartbeat. This is why the request must be renewed and this isillustrated in FIG. 4 by the periodic transmission of the HeartbeatRequests.

Another periodic process operating in CBRS is the Cooperative PeriodicActivities among SASs (CPAS) [2] process mentioned earlier. The fullcycle of CPAS is typically 24 hours and during this process each SASperforms a Full Dump Record that include information about all CBSDswith at least one active Grant, all existing Grants, location andantenna characteristics of the CBSDs as well as other information. Theinformation produced in Full Dump Record is then accessed by all otherSAS devices (other Spectrum Access Systems) so that each SAS has thedetails of all remaining SAS devices. As explained earlier, SASs areprovided by multiple vendors and the vendors must synchronize their SASsto allow interference modelling to be performed between vendors'equipment. As a result of the CPAS process certain grants may beterminated for various reasons, for example:

-   -   When conflicts between Grants are discovered, e.g. CBSDs having        approved grants from multiple SASs;    -   Grants whose frequency ranges are partially or fully overlapping        with certain Exclusion Zones (CBSD band used by the Federal        Government).

The inventors realised that because a failure of the CPAS process(resulting in Grant(s) remaining suspended) prevents the CBSD fromoperating there is a need for a solution using the CPAS process as a keyperformance indicator which should be monitored, and which shouldtrigger an alarm when a CPAS process failure is detected. For the CPASprocess to result in terminating Grant(s) is not a failure of the CPAS.In a successfully completed CPAS process the Grant is either authorisedor terminated. If the CPAS process fails, the Grant is suspended untilthe other SASs can be consulted and this prevents the CBSD fromoperating.

As it is now defined in the CBRS and CPAS specifications [1] and [2]there are two periodic processes running in a CBRS system:

-   -   1. CBSD—SAS Heartbeat Request/Heartbeat Response exchange        process with periodicity of several minutes. The period of        Heartbeat Requests is determined by local conditions—in        particular by the CBSD being located inside or outside an        exclusion zone. Range may be 60 seconds to 5 minutes.    -   2. CPAS process with Full Dump Record performed by each SAS and        filtering out of Grants than need to be terminated or suspended        as defined in reference [2]. The CPAS process is repeated with a        24-hour period.

If the CPAS process run on a SAS fails, the Grants already active onthis SAS will be suspended. The CPAS process may fail for example dueto: transmission problems, storage limitations or excessive server load.There may be other reasons for the CPAS process failure, but the causeof the CPAS process failure does not affect the operation of the presentsolution. Suspending a Grant may be caused for various reasons, some arelegitimate and well defined in the technical documentation, e.g.conflicts with other Grants or frequency range overlap discussedearlier, whereas suspending Grants caused by a CPAS failure prevents thesystem from operating even if the conditions for Grant suspensiondefined in the CPAS process are not met. This results in wasting unusedradio resources.

Further, the inventors realised that the possibility to identify andreact to a CPAS failure on a 24-hour basis is not satisfactory (this iswhen it would have been revealed that the CPAS process at a particularSAS failed). To address this problem, it is proposed to introduce a CPAStimer which triggers checking if a grant is suspended at a beginning andend of a CPAS interval (controlled by the CPAS timer). The CPAS timer issubstantially shorter than the 24-hours of the full CPAS process. If,indeed, the grant is suspended at the beginning and the end of the CPASinterval then an alarm may be raised which, in turn, may triggercorrective actions much earlier. This process is illustrated in FIG. 5and will be described in more detail in connection with description of anetwork illustrated in FIG. 6.

In one embodiment, illustrated in FIG. 6, a function of a Domain Proxy602 is used to fetch and maintain information indicative of Grants fromthe SAS 606. The information indicative of the Grants is maintained in adatabase 604 and polled (heartbeat) against the SAS 606, and theauthorization to transmit is used to control the CBSDs 608-612. Theinformation stored in the Grant database 604 can be used to monitor SASfunction, including Cooperative Periodic Activity between SASs (CPAS)functionality. Although the database 604 is illustrated as a separateunit it may, in some embodiments, be part of the Domain Proxy, 602, orother elements of the network operative to perform the method describedin this document.

In one embodiment, a timer, preferably in the Domain Proxy, is used tokeep track of when the CPAS process is run on the SAS, and how long itshould take (this is called CPAS interval). This can be used to predictcorrect CPAS behavior and to warn the network operator via an alarm orKPI when the CPAS fails.

The current version of document [2] describes the CPAS process andspecifies seven operations which are triggered at times T1, T2, T3 andT3+300 seconds. The times T1, T2 and T3 are determined and agreed uponby the SAS administrators. In alternative embodiments (and futureversions of the document [2]) the number of operations in the CPASprocess may be different than seven and the number of times specifiedfor performing these operations may also be different. These changes,however, would not change the operations of the present solution.

In a preferred embodiment of the method, illustrated in FIG. 5, the CPASinterval is the time needed for completing the operations of the CPASprocess. At commencement of the CPAS interval, 502, each Grant ischecked, 504 if it is not suspended. If, 504—No, the Grant has beenauthorized to transmit no further action is taken for this grant, 512.If the Grant exists but has been suspended since the commencement of theCPAS interval (i.e. no transmission is authorized), 504—Yes, then thesystem waits for the CPAS interval, 506, to allow the SAS to completethe CPAS operation. If, at the end of the CPAS interval, the Grant isstill allowed but the SAS has still not authorized transmission(resulting in the Grant still being suspended), 508—Yes, then the CPAShas failed and the system raises an alarm, 510. If, at the end of theCPAS interval the Grant is no longer suspended, 508—No, the Grant isauthorized. No further action is taken for this grant, 512. In apreferred embodiment the method may be performed in the Domain Proxy,602, and in alternative embodiments the method may be performed in CBSDdevices, 608-612, or even in the SAS, 606. When the method performed ina CBSD there is one instance of the method running in the CBSD for theCBSD (preferably in each one of the CBSDs 608-612). Irrespective ofwhere the method is executed it may be executed for one CBSD or, in analternative embodiment, it may be executed for multiple CBSDs.

If the SAS concludes during CPAS that no transmission is possible thenthe grant will be terminated. Termination of a Grant is not a faultcondition.

CPAS failures can be distinguished from other problems with obtaining aGrant to transmit, allowing new Grants to be requested where needed.

The important step here is to use the state of the Grants given andknowledge of the timing of the CPAS process in the SAS to deduce thesuccess or failure of CPAS operation. This information is not providedby the SAS but may be inferred from SAS behavior. The method describedis a way to monitor SAS behavior just from the information required bythe SAS-CBSD specification. For example, if the Grant Request wassuccessful the Grant is active, transmission cannot commence until theCBSD 608 is authorized to transmit as shown in FIG. 3. Therefore, whenthe CPAS process is performed a Grant suspended at the beginning of theCPAS interval at the end of the CPAS interval is expected to be eitherterminated for one of the reasons defined in reference [2] orauthorized. Termination and authorization indicate that the CPAS processhas been performed. If, however, the suspended Grant remains suspendedat the end of the CPAS interval then it may indicate that the CPASprocess failed and an alarm is raised, 510.

In one embodiment, the alarm is raised, 510, if the same is observed forother CBSDs 610, 612, associated with the Domain Proxy 602 (i.e. Grantsbeing suspended at the beginning and remaining suspended at the end ofthe CPAS interval). This means that in one embodiment the methoddescribed above and illustrated in FIG. 5 is performed for at least twoCBSDs associated with the same Domain Proxy (and the same SAS) and thealarm is raised when the CPAS process failure determined for one of theCBSDs is corroborated by the same results for the remaining CBSDs forwhich the method is executed.

The advantage of this solution is that the CPAS timer (CPAS interval) issubstantially shorter than the 24-hours for making the Full Dump Recordand hence the operator will be aware of the CPAS failure much earlierand the alarm raised may trigger corrective actions much earlier.

FIG. 9 and the following description will explain the timing of theoperations of the present solution in the overall context of the CPASprocess. At time T1 the CPAS process starts and each SAS produces a fullactivity dump (full dump record). This is repeated every 24 hrs. At timeT2 each SAS accesses the full dump records of all other SASs. Each SASfilters out Grants that need to be terminated and performs steps neededto terminate these Grants. At time T3 the Grants that need to beterminated are terminated and at time T3+300 seconds remaining Grantsare authorized. The value of 300 seconds is set in reference [2], but itmay be set at a different value.

The problem the present solution solves is that if the CPAS processfails there may be suspended Grants after the time T3+300 seconds andthe next opportunity to find this out is the next full dump record. Thetimes T1, T2 and T3 are to be agreed by SAS administrators, but in anycase, from start to complete at the T3+300 seconds it would take muchless than 24 hrs, which means that, the Grants suspended at the end ofthe process would be left undiscovered until the next full dump record.This is why the present solution introduces a check if there are anysuspended Grants at T1 (or beginning of CPAS) that are also suspendedthe end of the CPAS (slightly beyond T3+300 sec), this is the CPASinterval illustrated in FIG. 9. The check is done without waiting 24hrs, but at much shorter interval (CPAS interval).

Further, the disclosed solution considerably reduces the chance that thealarm will be triggered by incumbent protection problems. So, forexample, a Navy boat arriving during the 24-hour period will onlytrigger the alarm if it arrives between the CPAS interval completing andthe CPAS timer expiring. The Navy boat will still stop CBSDstransmitting but the problem will not be mis-identified as a CPASfailure.

FIG. 7 illustrates one embodiment of an apparatus, 700, which implementsthe method for monitoring performance of Cooperative Periodic Activitybetween Spectrum Access Systems (CPAS) process in a network operatingCitizens Broadband Radio Service (CBRS) described earlier. Theapparatus, 700, comprises a processing circuitry, 702, and a memory,704. The memory, 704, contains instructions executable by the processingcircuitry, 702, such that the apparatus, 700, is operative to perform afirst check of a status of a transmission Grant of a Citizens BroadbandRadio service Device (CBSD) at the start of the CPAS process and toperform a second check of the status of said transmission Grant at theend of the CPAS process, 506, if the result of the first check indicatesthat the Grant is suspended. Further, the apparatus, 700, is operativeto raise an alarm, 510, if the result of the second check indicates thatthe Grant is suspended, 508—Yes.

The apparatus, 700, may include processing circuitry (one or more thanprocessor) 702 coupled to the interface(s) 706, and to the memory 704.By way of example, the interface(s) 706, the processor(s) 702, and thememory 704 could be connected in series as illustrated in FIG. 7.Alternatively, these components 702, 704 and 706 may be coupled to aninternal bus system of the apparatus, 700. The memory 704 may include aRead-Only-Memory (ROM), e.g., a flash ROM, a Random Access Memory (RAM),e.g., a Dynamic RAM (DRAM) or Static RAM (SRAM), a mass storage, e.g., ahard disk or solid state disk, or the like. The memory, 704, may includesoftware, 712, and/or control parameters, 714. The memory, 704, mayinclude suitably configured program code to be executed by theprocessor(s), 702, so as to implement the above-described method asexplained in connection with FIG. 5 and embodiments described in thisdocument.

The interface, 706, is for connecting the apparatus, 700, to otherelements of the network operating Citizens Broadband Radio Service(CBRS).

It is to be understood that the structures as illustrated in FIG. 7 aremerely schematic and that the apparatus, 700, may actually includefurther components which, for the sake of clarity, have not beenillustrated, e.g., further interfaces or processors. Also, it is to beunderstood that the memory 704 may include further program code forimplementing other and/or known functionalities.

According to some embodiments, also a computer program may be providedfor implementing functionalities of the apparatus 700, e.g., in the formof a physical medium storing the program code and/or other data to bestored in the memory 704, or by making the program code available fordownload or by streaming.

It is also to be understood that the apparatus 700 may be provided as avirtual apparatus 700. In one embodiment, the apparatus 700 may beprovided in distributed resources, such as cloud resources. Whenprovided as a virtual apparatus, it will be appreciated that the memory704, processing circuitry 702, and interface 706 may be provided asfunctional elements. The functional elements may be distributed in alogical network and not necessarily be directly physically connected. Itis also to be understood that the apparatus 700 may be provided as asingle-node device, or as a multi-node system.

FIG. 8 illustrates one embodiment of a network operating in accordancewith embodiments of the method disclosed in this document. FIG. 8illustrates additional components of a wireless mobile communicationsnetwork compared with what is illustrated in FIG. 5 to better illustratethe context in which the present solution operates. Network operatorsmay deploy 4G and 5G wireless networks using the CBRS band. For this towork the SAS, 606 and 806, must authorise their associated CBSDs 608-612and 808. For clarity and brevity FIG. 8 only shows CBSDs associated withSAS 1, 606. Once the CBSDs are authorised they will use the CBRS band,or part of it for which their grants are authorised, for providingservice to user equipment 802. In this embodiment the CBSDs 608-612 maybe the eNodeBs that normally operate in LTE bands and CBSD 4, 808, maybe an access point providing access only in the CBRS band. The CBSDs608-612 and 808 are connected to the evolved packet core (EPC) network,804. Cooperation between SAS 1 and SAS 2 in the CPAS process is alsoillustrated. The same considerations are applicable to 5G networksdeployments.

ABBREVIATIONS

-   CBRS Citizens Broadband Radio Service-   CBSD Citizens Broadband Radio service Device-   CPAS Cooperative Periodic Activity between SASs-   DP Domain Proxy-   EPC Evolved Packet Core-   SAS Spectrum Access System

REFERENCES

-   1. “Signaling Protocols and Procedures for Citizens Broadband Radio    Service (CBRS): Spectrum Access System (SAS)—Citizens Broadband    Radio Service Device (CBSD) Interface Technical Specification”,    published by WinnForum, document WINNF-TS-0016 Version V1.2.2-   2. “Spectrum Sharing Committee Policy and Procedure Coordinated    Periodic Activities Policy”, published by WinnForum, document    WINNF-SSC-0008 Version 1.1.0

The invention claimed is:
 1. A method of monitoring Cooperative PeriodicActivity between Spectrum Access Systems (CPAS) process in a networkoperating Citizens Broadband Radio Service (CBRS), the methodcomprising: after the end of a CPAS interval, performing a check thatproduces a positive result if there is a transmission Grant that wassuspended at the beginning of the CPAS interval and also suspended afterthe end of the CPAS interval; and raising an alarm if the result of thecheck is positive.
 2. The method according to claim 1, comprising:performing a first check of a status of a transmission Grant of aCitizens Broadband Radio service Device (CBSD) at the start of the CPASprocess; if the result of the first check indicates that the Grant issuspended then performing a second check of the status of saidtransmission Grant at the end of the CPAS process; and raising an alarmif the result of the second check indicates that the Grant is suspended.3. The method according to claim 2, further comprising starting a timerat the start of the CPAS process, wherein the timer expires at theexpected completion of the CPAS process.
 4. The method according toclaim 1, performed based on information on a single Grant from one CBSD.5. The method according to claim 4, wherein a plurality of instances ofthe method are performed for a plurality of CBSDs.
 6. The methodaccording to claim 1, performed based on information on plurality ofGrants from a plurality of CBSDs, the plurality of CBSDs beingassociated with the same SAS, wherein the alarm is raised if Grants aresuspended at the beginning and at the end of the CPAS process for morethan one of the CBSDs.
 7. The method according to claim 1, performed ata Domain Proxy (DP), wherein the Domain Proxy represents one or moreCBSDs to the SAS.
 8. The method according to claim 1, performed at aCBSD.
 9. The method according to claim 1, performed at a SAS.
 10. Anapparatus for monitoring Cooperative Periodic Activity between SpectrumAccess Systems (CPAS) process in a network operating Citizens BroadbandRadio Service (CBRS), the apparatus comprising a processing circuitryand a memory, the memory containing instructions executable by theprocessing circuitry such that the apparatus is operative to: after theend of a CPAS interval, perform a check that produces a positive resultif there is a transmission Grant that was suspended at the beginning ofthe CPAS interval and also suspended after the end of the CPAS interval;and raise an alarm if the result of the check is positive.
 11. Theapparatus according to claim 10, operative to: perform a first check ofa status of a transmission Grant of a Citizens Broadband Radio serviceDevice (CBSD) at the start of the CPAS process; perform a second checkof the status of said transmission Grant at the end of the CPAS processif the result of the first check indicates that the Grant is suspended;and raise an alarm if the result of the second check indicates that theGrant is suspended.
 12. The apparatus according to claim 11, furtheroperative to start a timer at the start of the CPAS process, wherein thetimer expires at the expected completion of the CPAS process.
 13. Theapparatus according to claim 10, operative to use information on asingle Grant from one CBSD.
 14. The apparatus according to claim 10,operative to use information on plurality of Grants from a plurality ofCBSDs, the plurality of CBSDs being associated with the same SAS, and toraise the alarm if Grants are suspended at the beginning and at the endof the CPAS process for more than one of the CBSDs.
 15. The apparatusaccording to claim 10, comprising a Domain Proxy, wherein the DomainProxy (DP) is operative to represent one or more CBSDs to the SAS. 16.The apparatus according to claim 10, comprising a CBSD.
 17. Theapparatus according to claim 10, comprising a SAS.
 18. A communicationsnetwork comprising an apparatus for monitoring Cooperative PeriodicActivity between Spectrum Access Systems (CPAS) process in a networkoperating Citizens Broadband Radio Service (CBRS) wherein the apparatuscomprises a processing circuitry and a memory, the memory containinginstructions executable by the processing circuitry such that theapparatus is operative to: after the end of a CPAS interval, perform acheck that produces a positive result if there is a transmission Grantthat was suspended at the beginning of the CPAS interval and alsosuspended after the end of the CPAS interval; and raise an alarm if theresult of the check is positive.
 19. The communications networkaccording to claim 18, wherein the apparatus is further operative to:perform a first check of a status of a transmission Grant of a CitizensBroadband Radio service Device (CBSD) at the start of the CPAS process;perform a second check of the status of said transmission Grant at theend of the CPAS process if the result of the first check indicates thatthe Grant is suspended; and raise an alarm if the result of the secondcheck indicates that the Grant is suspended.
 20. The communicationsnetwork according to claim 19, wherein the apparatus is furtheroperative to start a timer at the start of the CPAS process, wherein thetimer expires at the expected completion of the CPAS process.
 21. Thecommunications network according to claim 18, wherein the apparatus isoperative to use information on a single Grant from one CBSD.
 22. Thecommunications network according to claim 18, wherein the apparatus isoperative to use information on plurality of Grants from a plurality ofCBSDs, the plurality of CBSDs being associated with the same SAS, and toraise the alarm if Grants are suspended at the beginning and at the endof the CPAS process for more than one of the CBSDs.
 23. Thecommunications network according to claim 18, comprising a Domain Proxy,wherein the Domain Proxy is operative to represent one or more CBSDs tothe SAS.